Fusion heat recovery and combustion gases filtering system with electric power production

Abstract: Such comprises providing every oven (1) used in the plant, over the exhaust passage (2) as such, with an operative unit (3) that works with an input exchanger (4) and a filter (5) that allows most of the waste products carried by the fumes to be recovered and sent back to the oven (1) and hence recycled. The operative units (3) of the various ovens (1) are associated in parallel to a joint water circuit (8) wherein a single output exchanger (9) is provided, that is in turn associated to a turbogenerator (10), in which the secondary circuit (11) of the exchanger (9) uses a high molecular mass organic fluid to drive a turbine (12) that in turn drives the alternator (13) that generates electric power.

Description: SPECIFICATION OBJECT OF THE INVENTION The present invention relates to a new heat recovery and gases filtering system at the output of industrial fusion ovens with which a high yield is achieved in the production of electric power, and the fumes are perfectly scrubbed and the waste products obtained are recyclable. The process subject hereof stems from a special application in the glass-ceramics and chemical industry but is equally applicable in a different field where a similarly high level of performance is required. BACKGROUND OF THE INVENTION Combustion fumes in industrial fusion ovens are currently either let off directly into the atmosphere, with the problems this entails from the standpoint of both environmental pollution and waste of energy, or go through a filtering stage to be scrubbed, in which event they must first pass through a heat exchanger in which the heat energy of the fumes is extracted in order to cool the same down and enable their mechanical filtering using conventional cap filters. The heat absorbed by the exchanger can be used directly or indirectly, whereas the waste products extracted from fumes can be disposed of or recycled. In certain industrial fields, however, for instance when obtaining an enamelling frit, within the aforesaid' ceramic field, various ovens need to be used, each of which produces a particular kind of enamel. This means that with current filtering systems for combustion gases, the waste products are mixed and, being different per se, since originating in ovens using likewise different raw materials, there is no way that they can be reused, wherefore the said waste products must be thrown out. Bearing in mind that a normal ceramic enamelling plant uses twelve ovens and each oven generates some 70 kg/day of waste products carried by the exhaust gases, clearly the amount of raw material wasted is significant and it is extremely important for the same to be recyclable. DESCRIPTION OF THE INVENTION The heat recovery and combustion gases filtering system subject of the invention has been devised in order to fully solve the foregoing problems, on the one hand making the most of the energy and on the other enabling full recycling of the waste products obtained from filtering. More specifically and in order to achieve the above, the system subject hereof is based upon the provision of an operative filtering unit for each oven used in the plant, obviously working with the respective heat exchanger allowing such filtering to be carried out under the best possible conditions, such operative unit being located over the oven exhaust passage as such to obtain hot water using such exchanger, at a temperature ranging between 90 and 150°C, and cold fumes allowing flexible bag or cap filters to be used, from which waste products are obtained that are recyclable back to a specific and unitary oven, since originating therein. The various exchangers working with the respective ovens are interconnected in parallel and associated to a joint circuit that has a second heat exchanger that relates the said circuit, which is preferably a water circuit, to a second circuit wherein a high molecular mass organic fluid flows, in charge of moving a turbine and through the same a respective alternator generating electric power, i.e. constituting an organic cycle turbogenerator. DESCRIPTION OF THE DRAWINGS In order to provide a fuller description and contribute to the complete understanding of the characteristics of this invention, a single sheet of drawings is attached to the specification which, while purely illustrative and not fully comprehensive, contains an only figure that schematically shows a fusion heat recovery and combustion gases filtering system, with electric power production, wherein two ovens are used. PREFERRED EMBODIMENT OF THE INVENTION With reference to the figure, it is clear that the system subject hereof is specifically applicable to plants using a variable number of ovens (1-1'), the system comprising the provision over the exhaust passage (2) as such in every oven (1) of an operative unit (3) working with a heat exchanger (4) to cool the gases or fumes down to a suitable temperature in order for the same to be filtered as best as possible in a self-cleaning textile bag or cap filter (5) in such a way that the waste products extracted by the filter (5) can reach a manifold (6) from which they can again move into the oven (1) to be recycled, according to the arrow shown in the figure, the filter (5) working with a conventional aspirator (7) that expedites the flow of the gases. The said exchanger (4) is associated to a circuit (8), preferably a water circuit, although oil or heat transmission fluid can also be used, all the operative units (3) of the various ovens (1) meeting at this water circuit (8), as the figure also shows. This water circuit (8) has associated a second exchanger or output exchanger (9) through which the water heated in the input exchangers (4) to a temperature ranging between 90 and 150°C transmits its heat to a turbogenerator (10), with a circuit (11) that has a high molecular mass organic fluid to drive a turbine (12) to which an alternator (13) is associated for the generation of output electric current (14). More specifically, the exchangers (4) and (9) have self-cleaning tubular bundles, and use gas flows through the exchange surface that enable self-cleaning with mechanical means. The powder contained in the exhaust gases of every oven can thereby be separated and hence be used in the relevant oven, thereby increasing frit production and drastically reducing the amount of waste powder to be disposed of. The plant layout is at the same time not adversely affected by the presence of long and large diameter insulated passages carrying the gases from the ovens to the single filtering sections. The heat energy carried by combustion gases is at the same time made the most of with a high level of electric power production.

Claims: A fusion heat recovery and combustion gases filtering system with electric power production, especially applicable to ceramic enamelling plants and the like where several ovens (1) are used with various kinds of enamel, said system comprising: a plurality of operative filtering units (3), one for each oven (1), each of said filtering unit comprising an input heat exchanger (4) for cooling the fumes coming from said oven (1) to an ideal temperature for filtering the same, a textile bag or cap filter (5) for recovering particles contained in said cooled fumes, and means for sending the particles recovered in said filter (5) back to the oven (1); a water circuit connecting the input heat exchangers (4) to an output heat exchanger (9), wherein said input heat exchangers (4) are connected in parallel to said water circuit (8); and an organic cycle turbogenerator (10) to which the heat absorbed by the input heat exchangers (4) is transmitted by said output heat exchanger (9). A fusion heat recovery and combustion gases filtering system with electric power production, as in claim 1, wherein the operative units (3) are arrangeable in the exhaust passages (2) of said ovens (1), and are connected by means of passages of small diameter to the water circuit (8) and through the latter to the output exchanger (9). A fusion heat recovery and combustion gases filtering system with electric power production, as in the above claims, wherein the turbogenerator (10) is provided with a secondary circuit (11) for the output heat exchanger (9) through which a high molecular mass organic fluid flows, which circuit (11) is provided with a turbine (12) driving an alternator (13) that generates electric power into which the heat energy extracted by the input heat exchangers (4) from the fumes as they leave the ovens (1) is transformed.

Inventors: NEBOT APARICI ANTONIO, NEBOT APARICI, ANTONIO
Applicants: COLOROBBIA ESPANA SA, COLOROBBIA ESPANA, S.A.
Application year: 1994
Main classification: F01K25
IPC codes: F27D17, F01K3, C03B5